diff --git a/identify/extensions.py b/identify/extensions.py
index f877350..6421ce0 100644
--- a/identify/extensions.py
+++ b/identify/extensions.py
@@ -267,6 +267,7 @@
     'tac': {'text', 'twisted', 'python'},
     'tar': {'binary', 'tar'},
     'targets': {'text', 'xml', 'msbuild'},
+    'td': {'text', 'tablegen'},
     'templ': {'text', 'templ'},
     'tex': {'text', 'tex'},
     'textproto': {'text', 'textproto'},